Recently, much research has been conducted on autonomous navigation of a vehicle. Typically, autonomous navigation means that an ECU mounted in a vehicle controls the vehicle to travel from a specific start point to an end point on a road according to predetermined logic, using GPS position information and various sensors based on road map information.
The autonomous navigation must be able to be applied to arbitrary roads including a crossroad, a forked road, and a tunnel as well as a straight road. Thus, the ECU must accurately recognize a traveling lane on a road. For example, when a vehicle is to make a left turn on a crossroad, a lane through which the vehicle can make a left turn is fixed on the crossroad. Thus, when the vehicle departs from the fixed lane, an accident may occur.
In general, conventional GPS devices have a positional deviation of 20 to 30 m. Thus, the conventional GPS devices cannot precisely recognize a traveling lane. However, a recently-developed differential GPS (DGPS) device has a positional deviation of about 1 m. Since general roads have a width of 3 to 5 m, traveling lane information recognized through the DGPS device may enable autonomous navigation.
However, the DGPS device is very expensive. Thus, when the DGPS device is mounted in a vehicle, the price of the vehicle rapidly increases. That is, there is a fundamental limit in mounting an autonomous navigation system using the DGPS device on a vehicle.